[Cc Alexander - email thread starts http://lkml.kernel.org/r/20181116101222.16581-1-osalvador@xxxxxxxx] On Fri 16-11-18 11:12:20, Oscar Salvador wrote: > From: Michal Hocko <mhocko@xxxxxxxx> > > arch_add_memory, __add_pages take a want_memblock which controls whether > the newly added memory should get the sysfs memblock user API (e.g. > ZONE_DEVICE users do not want/need this interface). Some callers even > want to control where do we allocate the memmap from by configuring > altmap. This is currently done quite ugly by searching for altmap down > in memory hotplug (to_vmem_altmap). It should be the caller to provide > the altmap down the call chain. > > Add a more generic hotplug context for arch_add_memory and __add_pages. > struct mhp_restrictions contains flags which contains additional > features to be enabled by the memory hotplug (MHP_MEMBLOCK_API > currently) and altmap for alternative memmap allocator. One note here as well. In the retrospect the API I have come up with here is quite hackish. Considering the recent discussion about special needs ZONE_DEVICE has for both initialization and struct page allocations with Alexander Duyck I believe we wanted a more abstracted API with allocator and constructor callbacks. This would allow different usecases to fine tune their needs without specialcasing deep in the core hotplug code paths. -- Michal Hocko SUSE Labs
